This project will use qualitative and quantitative approaches to assess the attitudes of the general public and of scientists about a proposed large U.S.-based cohort study on the role of genes and environment in health and disease. The project will build on the findings, expertise, infrastructure, and research team developed under the pilot public consultation project to address key questions raised by that project. The specific aims are: Aim 1: Assess public attitudes about research and the nature of the researcher-participant relationship as they relate to large cohort research. Aim 2: Assess public attitudes about information collected for or discovered as part of large cohort research. Aim 3: Assess human genetics researchers'attitudes about the proposed large cohort study. Issues identified in the initial Public Consultation Project will be explored in more detail through a series of focus groups with members of the public. Specific attention will be given to groups with social and demographic characteristics found in the initial consultation to be associated with particular views about the large cohort study and willingness to participate. Focus group findings will inform the design of a large nationally representative survey to quantitatively evaluate focus groups findings. The views of genetics researchers about the large cohort study also will be assessed through a series of interviews and a survey. This will allow evaluation of where researchers and the public agree or diverge on key issues including return of research results, consent, and privacy. Public Health Relevance: A large cohort study on the role of genes and environment in health could have enormous public health impacts but would be logistically complex and expensive. Funders, researcher, and the public are unlikely to commit to such an endeavor without evidence that the study can meet recruitment goals and successfully collect and analyze data. This project collects additional input needed to inform the design of the study.